Pencil



A. C. WELLS June 18, 1935.

PENCIL Original Filed Aug. 30, 1930 bbm cal/w, 51 1% 544M, Gamma/MPatented June 18, 1935 viris'mrss ZdgtBAtS 'ATEN FFlE Application August30, 1930, Serial No. 473,827 Renewed November 1d, 1934 3 Claims.

The invention relates generally to pencils and more particularly tomechanical pencils of the type in which a length of lead or otherwriting medium is slidably mounted substantially axially of the body ofthe pencil and projected to operative position from an end thereof.

One object of the invention is to provide a new and improved means for,projecting the lead from a mechanical pencil which is simple, compactand economical oi'manufacture and such as to positively drive the leadto operating position.

Another object of the invention is the provision of means toprogressively feed the lead of a pencil of the character described towriting position as an incident to the wear occasioned by its use. a

A further object of the invention is the production of a pencil of thecharacter described embodying feeding means adapted to advance a writingmedium in increments of varying extent without necessitating temporarycessation of use of the pencil.

Yet another object of the invention is the provision of a fullyautomatic mechanical pencil in which the writing medium is urgeddownwardly into writing position by a continuously acting feeding means,the operation of which is controlled by a releasable detent. I

Another object of the invention is to provide mechanical pencil in whicha spring pressed plunger constantly exerts an eiiort to project thewriting medium externally of the pencil and is normally restrained bythe action of an elongated wedge carried in an axial slot of a springpressed sliding sleeve member which journals the lead and projectsslightly beyond the truncated end of the cone-shaped extremity of thepencil, the sleeve member forcing the wedge downwardly into therestricted conical end of the pencil where its converging walls exertlateral eiiort on the wedge to bind the lead against movement in thesleeve. j

Ancillary objects and advantages will become apparent from the followingdescription of a preferred embodiment of the: invention and in theaccompanying drawing, in which:

Figure l is a vertical longitudinal sectional View. 7

Fig. 2 is a sectional view taken on line 2--2 of Fig. 1. I

Fig. 3 is a sectional view taken on line 3 -3 of Fig. 1.

For purposes of description, I have illustrated in the drawing and willhereinafter describe in detail the preferred embodiment of the inventionwith the understanding that I do not intend to limit the invention tothe particular construction and arrangement shown, it being contemplatedthat various changes may be made by those skilled in the art withoutdeparting from the spirit and scope of the appended claims.

Referring to the drawing, the invention in its preferred form isembodied in a pencil having an elongated cylindrical barrel ibfwhich maybe formed of metal or other suitable material, its upper end defining acircular opening it, its

lower end being tapered as at it to provide a relatively short truncatedconical section l3.

The writing medium, which in the present instance is a short length oflead M is slidably mounted for movement longitudinally of its principalaxis in an axial bore E5 of a guiding and supporting member it. Means isprovided to centrally align the inner end of the guide It in the body ofthe pencil and comprises in this embodiment of the invention a circulardisk shaped element ll, the under surface of which is formed with anaxial bore i8 adapted to receive the upper end of the guide.Communicating with the bore it? in the disk ll is a smaller concentricupwardly extending bore is defined by an integrally formed bearingsleeve 20.

A cylindrical, axially disposed lead receptacle 2! having side walls 22and bottom 23 is removably supported adjacent the open end of the barrelid with its lower walls 22 in spaced relation tothe inner surface of thewalls of the barrel. In this instance the lead receptacle is formed withan enlarged threaded shoulder 24 which is adapted for engagement with acomplementary thread 25 provided on the inner surface of the barreladjacent its open end H.

The threaded shoulder 25 of the lead receptacle 2!! projects externallyof the open end of the barrel to receive a threaded collar 26, the upperend of which is crimped inwardly as at 2i to engage an annular groove 28in an eraser 29. It will be seen that the collar 26 is readily removedfor the purpose of aiiording access to the lead receptacle or to permitrenewal of the eraser. Removal of the lead receptacle from the barrel isfacilitated by a diametrical notch 3E! formed in the peripheral edge ofthe collar 2% and adapted to receive the blade of a screwdriver.

The disk ii is slidably fitted in the barrel of the pencil, its limitingdownward position being determined by the point at which the sides ofthe barrel converge .inwardly to form the conical section 23. Torestrict the disk against displacement from its proper position, asillustrated in Fig. 1, a longitudinally extending yoke 3! is provided,the legs of which act between the bottom 23 of the receptacle 2! and theupper surface of the disk.

A pair of diametrically disposed sockets 32 formed in the upper face ofthe disk serve to correctly position the lower legs of the yoke and asmall knob 33 provided at the junction of the respective legs is adaptedto engage a complementaryindentation 3 struck upwardly in the bottomwall 23 of the lead receptacle. It will be seen that when the leadreceptacle is screwed into position in the upper end of the pencilitsbottom wall will abut the yoke to retain the disk I! in position.

Feeding means is provided to yieldingly urge the lead downwardly towriting position; To this end a plunger 35, reciprocably'mounted in thebearing sleeve 20 is adapted to be forced downwardly into abuttingengagement with the upper end' of the lead by an expansive coiled spring36 acting between the former part and a relatively stationary element ofthe pencil. Referring particularly to Fig. 1 the spring 3% will be seento be guided for movement in the annular space provided between theexternal suIfa'c-eof' the walls of the lead receptacle and the adjacentinner surface of the body of the pencil with its stationary end 3? inabutment with an annular stop collar 38. To permit the use of springs ofvarying lengths and tension and for the further purpose of facilitatingadjustment of the feeding pressure of the par ticular spring in use, thecollar 38 is preferably movable longitudinally of the barrel. To thisend the collar 38 in the present embodiment of the invention .isprovided with an internal screw thread 38 adapted to engage acomplementary thread 38 formed on the external surface of the wall 22 ofthe lead receptacle 2!.

In operating from extreme compressed to extreme elongated position thespring 36 is flexed substantially one-half of the length of the barrel[0. It is accordingly desirable to employ a spring of greatest possiblelength to insure uniformity ofpressure throughout its operating range.To this end" the energy of spring 36 is exerted upon plunger 35 througha thimble-shaped connecting member 39, the side walls 36 of which extenddownwardly in spaced relation to the walls of the barrel a distancesubstantially equivalent to the length of bearing sleeve 20 andterminate in an annular seat Bl adapted to receive the mobile end 42 ofthe feeding spring. Thus the use of a spring of appreciably greaterlength than could otherwise be employed is made possible.

The plunger 35 may be rigidly secured to the connecting member 39 in anydesired manner as by peening over a short section 43 of reduced diameterwhich is projected through an aperture of suitable size formed in thetransverse wall 44 of the thimble. Movement of the thimble relative tothe yoke 31 is provided for by the formation of two similar apertures 45in the transverse wall 44' of the thimble in which the respective legsof the yoke are freely slidable.

The above described feeding meansis normally restrained against movementby an automatically operable detent which, in the present embodiment ofthe invention is adapted to frictionally engage an appreciablearea' ofthe surface of the lead. To this end an elongated radially extendingslot 46, which is formed in the guide IB'in communication withthe bore[5, is slidably fitted with a tongue 4! of somewhat lesser length thanthe slot, the tongue being formed with a surface 48 which is arcuatelyshaped to afford an extensive bearing engagement with the lead. It willbe apparent that the tongue 41 is capable of an incremental movementrelative to the guide. The tongue 41 is normally held in frictionalengagement with the lead by an integrally formed wedge 49 the cammingsurface 50 of which, in the present instance, cooperates with theconverging walls of the section l3 of the body as shown in Figs. 1 and3. Means is provided t'o'move the Wedge longitudinally of the barrel torelease the tongue 41 from binding engagement with the lead. To this endthe sleeve I6 is" longitudinally slidable in the bore l8 and is providedwith a journal 5| adjacent its lower end which is slidably received inthe truncated end of the conical section I3. mally urged to its downwardposition to move the wedge and tongue to locking position by a coiledexpansive'spring 52 which acts between the under surface of disk I! andannular collar 53 preferably formed integrally with the sleeve. It willbe apparent that the feeding means will normally be prevented frommoving the lead downwardly because of the inherent tendency of the wedge49 to move down and inwardly under the influence of spring 52 to forcethe tongue 41 into looking engagement with the lead.

The invention embodies means to automatically release the locking actionof the wedge as an incident to wearing of the writing medium to such anextent as to defeat further use of the pencil. In this particularembodiment of the invention the locking action of the wedge iscontrolled by the sleeve I6, the lower end of which protrudes beyond thetruncated lower end of the pencil at St. When the pencil is in use andthe writing medium has'been worn so as to permit the protruding end 54of the sleeve to lightly contact the paper, the sleeve will be movedupwardly against the action of the spring 52, the lower end of slot 46contacting the lower end of tongue i'l shortly thereafter to release thewedge 49 ,withits tongue 41 from binding engagement with the lead.Thereupon the'relatively stronger spring 35'will serve to drive the leaddownwardly through the medium of the piston 35 a sufiicient distance torelease the upward pressure upon the sleeve is whereupon the spring 52again moves the wedge downwardly to cause the tongue to resume itsbinding action upon the lead thereby stopping the feeding action. Thus,while the spring 36- is acting to drive the lead downwardly in a feedingmovement, the sleeve I6 is momentarily restrained in the position towhich it was 7 forced through contact with the writing surface. Hence,movement of the lead occurs relative to the tongue. As the downwardpressure on the sleeve is released, its spring 52 acts to force bothsleeve l6 and tongue 4'! downwardly to normal position, the wedge 49simultaneously cooperating with the converging lower end of the pencilto force the tongue into binding frictional engagement with the lead.

It will be-se'en that a wholly automatic mechanicalpencil has beenprovided in which the lead is continuously forced downwardly to writingposition under control of a locking means normally operable to prevent afeeding movement and automatically releasable as an incident to wearingof the lead to permit feeding action, thereby permitting uninterrupteduse of the pencil.

I claim as my invention:

1. A pencil comprising, in combination, an elongated tubular body havinga conically shaped lower end section, a sleeve slidably supportedcoaxially of said body with its lower end protruding externally of theconical end thereof, said sleeve having a longitudinal bore adapted tosupport a length of lead in position for writing and a radiallyextending slot communicating with said bore, spring means normallyurging said sleeve downwardly, a plunger slidable longitudinally in saidbore, spring means acting between said plunger and a stationary part ofsaid body to urge said plunger downwardly to feed a lead to writingposition, an elongated tongue projecting into the radially extendingslot therein, and being movable axially thereof, and a wedge memberfixed to said tongue and operable to force said tongue into bindingengagement with a lead when said sleeve is moved downwardly and torelease said lead for feeding movement when said sleeve is movedupwardly.

2. A pencil comprising, in combination, an elongated tubular body havinga conically shaped lower end section, a sleeve slidably supportedcoaxially of the body with its lower end protruding externally of theconical end thereof, said sleeve having a longitudinal bore adapted tosupport a length of lead in position for writing and a longitudinallyextending opening communicating with said bore, a clamping wedge movablein said opening radially with respect to said bore to clamp a lead insaid bore, a spring means normally urging said sleeve downwardly toengage said wedge with said conical lower end section and thereby movesaid clamping wedge to its active position, a plunger slidable in saidbore into endwise abutment with a lead positioned in the bore, andspring means acting constantly to urge said plunger against said leadand controlled in its feeding function by the restraining action of thewedge upon the lead.

3. A pencil comprising, in combination, an elongated tubular body havinga conically shaped lower end section, a sleeve slidably supportedcoaxially of said body with its lower end protruding externally of theconical end thereof, said sleeve having a longitudinal bore adapted tosupport a length of lead in position for writing, spring means normallyurging said sleeve downwardly, a plunger slidable longitudinally in saidbore, spring means acting between said plunger and a stationary part ofsaid body to feed a lead downwardly in said sleeve to writing position,a clamping wedge for securing the lead against movement by said plunger,said sleeve having a longitudinally extending opening therein throughwhich said wedge may be moved radially toward and into clampingengagement with the lead, said wedge having a slight axial movement insaid opening and being shiftable into binding engagement by cammingengagement with the inner surface of said conical lower end when thesleeve is moved downwardly, the lead being released by said wedge whenthe sleeve is moved upwardly.

ALBERT C. WELLS.

